Accepted Answer

Read the faq here on GameFaqs for all the controls.You talk to people by pressing the a button in front of them.Also when you jump on a Koopa and it drops something that looks like ash, stand on it and then jump to pick it up. Then you need to bring these artifacts to the information desks in the city and then answer some questions to get a photo.Repeat this for the other two artifacts you find and get those photos.While doing this, talk to people to find out in what city you are. If you have an idea, then press start and select the Gobulator option. Now walk Yoshi that city and press a button. If you where right you now have Yoshi, allowing you to exit the current city and walk twice as fast.When all the photos are collected you should go back to the blue pipe (look for it on the city map) and enter it. If you did everything right, you have successfully cleared that city and are ready to move to the next city.

Repeat this for the other four doors and then you have to fight one of Bowser's minions.Defeating him lets you move to the next floor.